The USB (Universal Serial Bus) connectors are currently very popular. Referring to FIG. 7, the USB connectors are easy to use. However, when a need exists in coupling a male plug B with a female socket A, an outer frame B2 of a terminal base (not shown) of the male plug B is hooked and confined merely by an outer frame A2 of a terminal base A1 of the female socket A so as to contact these two terminal bases with each other for transmitting signal.
The coupled USB connectors are able to provide good signal transmission. However, the coupled USB connectors, which are provided with no anti-decoupling structure, may be decoupled easily by inadvertent pull and drag, causing negative influence on signal transmission.
Whereas the foregoing description, the present inventor makes diligent studies in providing the consumers with an anti-decoupling structure to protect the USB connectors from being decoupled by pull and drag, thereby preventing the signal transmission from being affected.